[GraphQL] Use Transactions instead of chaining db operations in add comment function?

[thepassenger-hub]

Instead of using try/catch when we add the comment to the product we could use the transaction, so if there is an error in calculating the stars/adding the comment to the product document we dont have to delete the comment ourselves but an automatic rollback is performed.

https://mongoosejs.com/docs/transactions.html

[thepassenger-hub]

Fixed.